Synthesis and charge-discharge properties of 2LiF-NiF 2 composite and Li 2 NiF 4 as a cathode material for Li-ion batteries.

Abstract

2LiF-NiF2 composites are synthesized by the mechanical milling of LiF and NiF2 in a molar ratio of 2 : 1 for 72 h, and Li2NiF4 are synthesized by calcination at 673 K. The synthesized samples are investigated by XRD, cyclic voltammetry, and charge-discharge measurements. XRD peaks of the 2LiF-NiF2 composite are broad and the discharge capacity is 44 mAh/g at 0.05 C for voltages of 2.0-4.8 V. After calcination, the XRD peaks become sharp and most peaks are agreement with Li2NiF4. Li2NiF4 obtained by calcination shows a discharge capacity of 96 mAh/g at 0.05 C and 118 mAh/g at 0.02 C for voltages of 2.0-4.8 V. 2LiF-NiO composites are also obtained by the milling of LiF and NiO in a molar ratio of 2 : 1 for 72 h, and shows a discharge capacity of 146 mAh/g. The discharge capacity of 2LiF-NiO at 3C was maintained that of 70 % of 0.1C.